Synthesis and Characterization of Polypyrrole-Antimony ......nanocomposites . PPy-Sb 2 O 3...

Polymer Nanocomposites

3 3Assistant Professor of Physics,

Erode, Tamilnadu, India

Abstract-The PPy-Sb2O3 nanocomposites with Sb2O3

(< 250 nm) nanoparticles various weight percents were prepared

by mechanical mixing. Fourier transform infrared (FTIR)

spectroscopy, ultraviolet-visible (UV–Vis) spectroscopy, X-ray

diffraction (XRD), thermogravimetric analysis (TGA),

differential scanning calorimetry (DSC), scanning electron

microscopy (SEM), and energy dispersive X-ray analysis

spectroscopy (EDAX) were used to characterize the PPy-Sb2O3

nanocomposites. The FTIR results indicated that there are some

interactions between PPy and Sb2O3 nanoparticles. Such an

interaction is likely caused by the formation of the coordinate

bonding between the lone pair electron of atom in PPy chain with

orbit of Sb atom of Sb2O3, indicating a reduction in the strength

of PPy-Sb2O3 interactions as the wt % increases, which may lead

to the broader size distribution of Sb2O3 nanoparticles dispersed

in nanocomposites.

Schematic diagram PPy-Sb2O3 nanocomposites

The UV-vis results of PPy-Sb2O3 nanocomposites interactions

is significantly increased by increasing the Sb2O3 wt%, leading to

reduce the energy level interval of benzenoid ring and hence

result in a red shift. The XRD result indicates that PPy has been

successfully anchored on the surface of Sb2O3 nPs through the

mechanical mixing method. The morphology and elemental

composition analysis were characterized by using SEM and

EDAX. This result indicates high interaction between PPy and

metal oxides.

1. INTRODUCTION

Hybrid inorganic-organic nanocomposite materials

have attracted more and more attention due to creating new

materials which combine different functions and

characteristics of individual materials. Different inorganic

materials including carbon nanotubes, metal, metal oxides and

nanosheets have been investigated in polymer matrices [1].

Nanocomposite materials have attracted a lot of interest due to

their probable commercial exploitation as sensors, batteries,

toners in copying machines, quantum electronic devices, smart

windows and materials for electromagnetic shielding, etc.

Nanocomposite materials made from nanoparticles of oxides

and conducting polymers are the most interesting and

challenging areas of research in recent times [2]. The

conducting polymers, such as polythiophene, polypyrrole

(PPy) and polyaniline have been exhaustively studied due to

their outstanding mechanical and electrical properties, which

afford applications in actuators, sensors and electrochromic

devices [3]. Among the conducting polymers, PPy has

attracted considerable attention because it is easy synthesis, it

has relatively good quality environmental stability and its

surface charge characteristics are can be customized by

changing the dopant species into the material during the

synthesis [4,5]. In the present work, we report the fabrication

of conductive PPy-Sb2O3 nanocomposites using mechanical

mixing method. The chemical structures of the PPy-Sb2O3

nanocomposites are characterized by Fourier transform

infrared (FT-IR) spectroscopy and optical parameters are by

using UV-vis characterization. The thermal stability of the

PPy-Sb2O3 nanocomposites is performed by thermogravime -

tric analysis (TGA) and differential scanning calorimetric

(DSC). Scanning electron microscope (SEM) is used to

characterize the dispersion of Sb2O3 nPs and the morphology

of the PPy-Sb2O3 nanocomposites. The effects of the Sb2O3

nPs on the crystallization structures of the PPy are also

studied. In this present work, the inorganic-organic hybrid

nanocomposite containing polypyrrole as the organic part and

antimony (III) oxide as the inorganic part have been used for

studying structural, optical and thermal properties. Such types

of nanocomposite have shown to posses small grain size and

high stability. To the best of our knowledge, this is the first

Synthesis and Characterization of

Polypyrrole-Antimony (III) Oxide Hybrid

Dr. N Dhachanamoorthi Dr. M. Jothi1 2

1 2Assistant Professor & Head, Assistant Professor,

PG Department of Physics, Vellalar College for Women, PG Department of Physics, Vellalar College for Women,

Erode, Tamilnadu, India. Erode, Tamilnadu, India.

S. Tamilselvan

Nandha Arts and Science College,

International Journal of Engineering Research & Technology (IJERT)

ISSN: 2278-0181http://www.ijert.org

IJERTV8IS120339(This work is licensed under a Creative Commons Attribution 4.0 International License.)

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ever attempt made to synthesis and investe of these

nanocomposites with special properties.

2. EXPERIMENTAL

2.1. Materials

All of the chemical reagents used in this experiment

were A.R. grade. The monomer pyrrole (PPy) and

Dodecylbenzene Sulfonic acid (DBSNa) as dopant was

purchased from Aldrich Chemical and purified by distillation

under reduced pressure, stored in refrigerator before use.

Antimony (III) oxide nanopowder, <250 nm nanoparticle

(98% purity) from Aldrich Chemical, Ammonium

peroxydisulfate (99%, Merck), Ethonal (99% purity, Merck),

Acetone (99% purity, Merck) were purchased from Merck

chemical. The water used throughout the work is distilled

water.

2.2. The preparation of polypyrrole (PPy)

The polypyrrole was synthesized by chemical

oxidation polymerization under static condition in a lower

temperature. About 900 ml of de ionized water was taken in a

flask and an arrangement for mechanical stirring.

Dodecylbenzene sulfonic acid solution (DBSNa) as a dopant

was dissolved in above 900 ml of deionized water and the

solution was well stirred in the flask. Monomer pyrrole was

added in the above suspension solution and keeps stirring for

30min. After 30 min ammonium peroxydisulfate (NH4)2S2O8

as an oxidant was added drop wise slowly to the good degree

of polymerization is achieved the suspension solution was

dark black in color. The entire solution mixture was

continuously stirred well at 0-5◦C and the reaction was

continued for another 24 h over all time speed of rotation

maintained at 700rpm. The product was filtered and washed

with deionized water, ethanol and acetone, then dried under

vacuum at 80◦C for 24 h. Experimental setup as shown in

Fig.1.

2.3. Synthesis of polypyrrole-Sb2O3 nanocomposites

PPy-Sb2O3 nanocomposites were synthesized using different

wt% of Sb2O3 with respect to polypyrrole which are referred

as PPy-Sb2O3 nanocomposites. Pure PPy was synthesized

following the same procedure without Sb2O3 nanoparticles.

The molar ratio of polymer (PPy) and metal Oxide Sb2O3 was

1:0.25 to prepare PPy-Sb2O3 (25%) nanocomposites by using

mechanical mixing method. Similarly the samples were

prepared in the different weight % of Sb2O3 nanoparticles like

PPy-Sb2O3 (50%) and PPy-Sb2O3 (100%) by the ratio 1:0.50

and 1:1 respectively.

3. CHARACTERIZATION

FT-IR spectra of the pure PPy, PPy-Sb2O3

nanocomposites, Sb2O3 nPs samples were recorded at room

temperature using FT-IR Spectrometer Make: Perkin Elmer;

Model: Spectrum RX 1; Range: 400 cm-1-4000 cm-1;

Resolution: 4. The sample was prepared in the pellet form by

mixing the polymer powder with KBr by the ratio 1:10 and

pressing it in the Perkin Elmer hydraulic device using 15 ton

pressure.

Fig.1 Experimental setup for chemical oxidative polymerization method

UV-vis spectra of the synthesized PPy-Sb2O3

nanocomposites powder were determined using a UV–vis

spectrometer, Model: Lambda 35; Range: 400 nm-1100 nm;

Resolution: 4; Mode of operation: 1.Transmittance (T %) and

Absorbance (A %) 2. Reflectance (R %). X-ray diffraction

patterns of PPy-Sb2O3 nanocomposites samples performed

using advance diffractometer with monochromatic CuKα

radiation (λ=1.54Å) are used to identify crystalline nature of

the samples. The crystallite size was determined from Scherrer

relation.

(1)

where, D is the crystallite size, K is the shape factor for the

average crystallite (w0.9), λ is the wavelength of the X-ray

which is 1.54 Å for Cu target, B is the full width at half

maxima of the crystalline peak in radians, θ is the angle

between incident and reflected rays. Thermogravimetric

properties of the pure PPy and PPy-Sb2O3 nanocomposites

were studied in instrument used: STA449 F3 Jupiter;

Temperature range: RT to 500 ºC; Heating rate: 10K/min;

Atmosphere: Nitrogen; Sample Carrier: TG-DSC Sample

Carrier; Sample Crucible: TG-DSC Alumina Crucible with

lid. The microstructure, size and morphology of the

synthesized polypyrrole as well as their dispersity in the PPy-

Sb2O3 nanocomposites could be determined with the help of

scanning electron microscopy (SEM) images were obtained on

Make: JEOL; Modal: JSM 6390; Made in Japan. Energy

dispersive X- ray spectroscopy employed to analyze the

chemical compositions of nanocomposites was carried out

using Make: Oxford Instruments; Modal: INCA Pental FET 3;

Made in England.

4. RESULT AND DISCUSSION

4.1 FTIR spectral analysis

The FTIR spectra of pure PPy, PPy-Sb2O3 (25-100%)

nanocomposites and pure Sb2O3 nPs are shown in Fig.2. The

main transmittance peaks of PPy are appeared at 3402.05 cm-1

and 1547.23 cm-1 could be corresponded to the N-H stretching

vibration and symmetric stretching vibration of C-C bond in

the PPy ring, respectively. The band at 1397.53 cm-1 is

assigned to N-H bending vibration bond. The transmittance




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peaks appeared at 1184.22 cm-1 and 905.96 cm-1 was

attributed to the in-plane bending vibration of C-H bond and

the C–H out-of-plane bending vibration indicating the

polymerization of pyrrole respectively [6]. The FTIR spectrum

of the PPy-Sb2O3 (25%) nanocomposite demonstrated the

peaks at 3396.57 cm-1, 1545.98 cm-1, 1381.84 cm-1, 1185.86

cm-1, and 908.86 cm-1 that are considered to arise from pyrrole

ring stretching, N-H stretching vibration, C-C symmetric

stretching vibration, N-H bending vibration, C-H in plane

bending vibration and C-H out-of-plane bending respectively.

The transmittance peaks and corresponding stretching

vibration of pure PPy, PPy-Sb2O3 nanocomposites was shown

in Table.1. These results confirmed the presence of PPy

moieties in the nanocomposites. Interestingly, all peak

positions shifted towards higher values after Sb ions

adsorption. The delocalized π electrons in PPy matrix, which

are involved in the skeletal vibration of PPy ring, are affected

by the doping ions in the polymer matrix. Different types of

dopants in the PPy backbone may disturb the conjugate

structure of PPy and this limit the extent of charge

delocalization along the polymer chains, leading to red shift.

However, as for PPy-Sb2O3 nanocomposites, except the peaks

of PPy, the broad band between 500 and 950cm-1 are

attributed to the Sb-O bond, suggesting that the Sb2O3 was

embedded in PPy matrix. The results indicated that there are

some interactions between PPy and Sb2O3 particles. Such an

interaction is likely caused by the formation of the coordinate

bonding between the lone pair electron of atom in PPy chain

with orbit of Sb atom of Sb2O3, indicating the strength of PPy-

Sb2O3 interactions, as the wt % increases, which may lead to

the broader size distribution of Sb2O3 particles dispersed in

nanocomposites. Compared to pure PPy, the characteristic

peaks of PPy-Sb2O3 nanocomposites slightly shifted to higher

wavelength, indicating the strong interaction at the interface.

Besides, the characteristic peaks of PPy-Sb2O3 are well

maintained in the nanocomposites, indicating that PPy has

been successfully compounded with Sb2O3 without changing

chemical composition. Comparing to the corresponding peaks

of pure PPy, the peaks of PPy-Sb2O3 shifted towards lower

wavenumber. This shifting of absorption bands may be due to

the action of hydrogen bonding between the hydroxyl groups

on the surface of Sb2O3 nPs and the amine groups in the PPy

molecular chains. Similar observations of absorption shifting

peaks of PPy-Sb2O3 towards are obtained in lower

wavenumber. This result indicates that the PPy-Sb2O3

nanocomposites have been successful synthesized and the

observed shift indicates the interaction between PPy and nPs.

Fig.2 FTIR spectra of pure PPy (a) and PPy-Sb2O3 nanocomposites (b, c & d)

Sample

Name

N-H

stretching

vibrations

(cm-1)

C–C ring

symmetric

stretching

vibrations

(cm-1)

N-H

bending

vibrations

(cm-1)

In-plane

C–H

bending

Vibrations

(cm-1)

Out-plane

C–H

bending

Vibrations

(cm-1)

Pure

PPy 3402.05 1547.23 1397.53 1184.22 905.96

PPy-

Sb2O3

(25%)

3396.57 1545.98 1381.84 1185.86 908.86

PPy-

Sb2O3

(50%)

3410.94 1548.74 1387.97 1187.47 911.61

PPy-

Sb2O3

(100%)

3373.71 1544.73 1395.43 1181.12 916.23

Table.1 FTIR data of pure PPy and PPy-Sb2O3 nanocomposites

4.2. UV-vis absorption spectral analysis

The UV-vis spectra of pure PPy (a), PPy-Sb2O3

(b,c, d) nanocomposites and pure Sb2O3 (e) are shown in

Fig.3. The absorption reveals that there is different

composition and morphology in ranging Sb2O3 concentration

from 25-100% in PPy-Sb2O3 nanocomposites. However, as the

characteristic absorption bands of pure PPy are obtained in the

wavelengths range of 250-300 nm, 450-450 nm and 900-1000

nm. UV-vis analysis was also conducted to analyze the PPy

are presented in Fig.4 (a), in which the intermediates exhibit

an absorption band appeared at about 473nm. This band is due

to the formation of phenazine-like structures in this stage.

These bands are assigned to the formation of PPy. The first

absorption band corresponds to the π-π* electron transition

within benzenoid segments. The second and the third bands

correspond to the doped state and the polaron formation in

PPy respectively. From the spectroscopic and theoretical data

indicate, that the absorption band at 400-500 nm (4-3 eV) is

assigned to π-π* transition of PPy. The band gap of each case

is determined from Tauc plot which is shown in Table.2.




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Fig.3 UV-vis spectra of pure PPy (a), PPy-Sb2O3 nanocomposites (b, c, d) and pure

Sb2O3 nPs

Sample

Name

Wavelength (nm) Absorption Band

gap

(eV) Band:

1

Band:

2

Band:

3

Band:

1

Band:

2

Band:

3

Pure

PPy 260 473 931 0.1826 0.1581 0.2017 3.46

PPy-

Sb2O3

(25%)

343 360 379 0.3393 0.4155 0.3951 3.04

PPy-

Sb2O3

(50%)

342 359 379 1.0751 1.4434 1.3211 1.76

PPy-

Sb2O3

(100%)

343 359 380 1.7405 1.7130 1.8569 1.49

Pure

Sb2O3 340 359 380 1.8181 2.0666 2.5913 1.71

Table.3 Crystallographic parameters of pure PPy,

PPy-Sb2O3 nanocomposites and pure Sb2O3 nPs

Among the various cases, the highest band gap energy was

obtained for pure PPy and then the band gap was decreased

with increasing Sb2O3 concentration which is clearly shown in

the Table.2. The PPy-Sb2O3 interactions is significantly

increased by increasing the Sb2O3 wt%, leading to reduce the

energy level interval of benzenoid ring and hence, result in a

red shift. The FTIR spectra of the nanocomposites shown in

Fig.3 also support this conclusion. Upon doping PPy exhibits

unusual electronic structure due to electron–phonon coupling.

Polarons and bipolarons states appear within the band gap,

which gives rise to the broad band at wave length 900-1000

nm in the case of pure PPy. Generally, the optical band gap in

a semiconductor is determined by plotting absorption

coefficients (α) as (αhν)1/m vs. hν where ‘m’ represents the

nature of the transition and hν is the photon energy. Now ‘m’

may have different values, such as , 2, and 3 for allowed

direct, allowed indirect, forbidden direct and forbidden

indirect transitions respectively.

(1)

where ‘A’ is the absorption constant for a direct transition. For

allowed direct transition one can plot (αhν)2 vs. hν as shown in

Fig.4 and extrapolate the linear portion of it to α=0 value to

obtain the corresponding band gap.

Fig.4a

The optical absorption coefficient (α) near the absorption edge

for direct interband transitions is given by the equation (1).

The band gap of PPy with antimony concentration implies that

electronic structure of PPy is affected [8,9]. UV-Vis spectral

data and the band gap of pure PPy, PPy-Sb2O3 (25-100%)

nanocomposites and pure Sb2O3 are as shown in Table.2.

Fig.4b




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Fig.4c

Fig.4d

Fig.4d

Fig.4e

Fig.4a-4e Tauc plot for (αhν)2 vs hν of pure PPy, PPy-Sb2O3 nanocomposites

and pure Sb2O3 nPs

4.3. X-Ray diffraction studies

Fig.5 shows the XRD patterns of pure PPy, PPy-

Sb2O3 nanocomposites (25-100%) and pure Sb2O3 nPs which

is a evidence of crystalline nature of the samples. The XRD

pattern of pure PPy shows a broad peak and sharp peak

appeared at 23.04º and 44.36º respectively, which indicates the

crystalline nature. XRD curve of PPy shows that the PPy

prepared in the absence of Sb2O3 nPs is amorphous in nature.

The crystallite sizes of the PPy were estimated from X-ray line

broadening using Scherer's formula. It can be seen clearly

from the XRD patterns of Sb2O3 nPs, that the Sb2O3 nPs

showed a single-phase in nature. There was no secondary

phase detected and the high intensity of the peaks revealed the

crystalline nature of the as Sb2O3 nPs. Obviously, the

diffraction peaks of the Sb2O3 nPs appear in the PPy-Sb2O3

nanocomposites from the Fig.5 (b,c,d) the intensity of these

peaks becomes stronger with increasing the nanoparticle

loadings, while the two original peaks of PPy show a reduced

intensity at 2θ=23.04 and 44.36º. The XRD pattern also

confirm the presence of antimony in the PPy-Sb2O3

(25-100%) nanocomposites and pure Sb2O3 the crystallize size

as-calculated, where the average crystallize size are 97 nm

(25%), 170 nm (50%), 176 nm (100%) and 152 nm

(pure Sb2O3). The strain and dislocation density of pure PPy,

PPy-Sb2O3 nanocomposites (25-100%), pure Sb2O3 nPs data

are seen in Table.3. The parameters are slightly changed with

the addition of Sb2O3 nPs. Furthermore, these results revealed

the amorphous nature of PPy in the nanocomposites,

suggesting that the addition of Sb2O3 nPs retain the

crystallization of the PPy molecular chains. This may be

because when PPy is adsorbed on the surface of the Sb2O3

nPs. The increasing trend intensity indicating that the Sb2O3

greatly increased due to the adsorption of PPy molecular

chains on the surface of the Sb2O3 nPs. In order to study the

effect of the addition of Sb2O3 nPs in PPy matrix, a careful

analysis of the position of the XRD peak indicates that, there

is a shifting in peak's position towards lowering 2θ value, but

in this case, the crystallinity of Sb2O3 nPs was found to be

disturbed in the PPy-Sb2O3 nanocomposites. However, in the

present work the crystallinity of Sb2O3 is not disturbed by PPy




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molecular chain on the surface of Sb2O3 nPs as can be seen

from Fig.6. The shifting of the peak's position clearly indicates

that PPy-Sb2O3 nanoparticles are incorporating into the PPy

polymer matrix. The broad weak diffraction peak of PPy still

exists, but its intensity decreases. This indicates a strong effect

of the Sb2O3 nPs on the structures of crystalline of the formed

PPy and the interaction between PPy backbone and Sb2O3 nPs.

Fig.5 X-Ray diffraction patterns of pure PPy (a), PPy-Sb2O3

nanocomposites

(b, c, d) and pure Sb2O3

nPs (e)

This result indicates that, PPy has been successfully anchored

on the surface of Sb2O3 NPs through the mechanical mixing

method. However, the characteristic peak intensities of

PPy-Sb2O3 nanocomposite gradually decreased with

increasing the weight percentage of Sb2O3, indicating the

incorporation of Sb2O3 into the polymer matrix. Previous

literature also support that the parent work that the

introduction of Sb2O3 will affect the crystalline behavior of

PPy [10-12].

Peak No

Pure PPy

2θ FWHM Intensity d Spacing

Value

Crystallize size

(nm) Strain Dislocation density

1 23.04 0.071 263 3.8570 114 0.0006 1.30*10-14

2 44.36 0.094 980 2.0404 91 0.0004 8.32*10-15

Peak No

PPy-Sb2O3 (25%)


Value

Crystallize size


1 13.88 0.118 130 6.3749 67 0.0018 0.20*10-15

2 27.80 0.118 1647 3.2065 69 0.0009 4.80*10-15

3 28.52 0.118 220 3.1271 69 0.0009 4.80*10-15

4 32.22 0.165 610 2.7760 50 0.0001 2.50*10-15

5 35.20 0.071 140 2.5475 117 0.0004 1.37*10-14

6 46.10 0.118 570 1.9673 73 0.0005 5.34*10-15

7 54.64 0.071 617 1.6783 125 0.0002 1.58*10-14

8 57.26 0.118 170 1.6076 76 0.0004 5.87*10-15

9 59.14 0.071 103 1.5609 128 0.0002 1.65*10-14

10 64.14 0.118 57 1.4507 79 0.0003 6.30*10-15

11 68.96 0.071 77 1.3606 135 0.0002 1.84*10-14

12 74.08 0.071 163 1.2787 140 0.0001 1.96*10-14

13 76.44 0.071 170 1.2450 142 0.0001 2.02*10-14

Peak No

PPy-Sb2O3 (50%)


Value

Crystallize size


1 14.00 0.047 213 6.3205 170 0.0007 2.89*10-14

2 27.94 0.047 1747 3.1907 174 0.0003 3.03*10-14

3 28.76 0.047 113 3.1016 174 0.0003 3.04*10-14

4 32.34 0.071 567 2.7659 116 0.0004 1.35*10-14

5 35.28 0.071 153 2.5419 117 0.0004 1.37*10-14

6 46.24 0.071 607 1.9617 121 0.0003 1.47*10-14

7 54.80 0.047 533 1.6738 190 0.0001 3.62*10-14

8 57.42 0.047 173 1.6035 192 0.0001 3.71*10-14

9 59.32 0.071 110 1.5566 128 0.0002 1.65*10-14

10 64.28 0.047 83 1.4479 199 0.0001 3.98*10-14

11 69.04 0.047 80 1.3593 205 0.0001 4.20*10-14

12 74.20 0.047 153 1.2770 211 0.0001 4.48*10-14

13 76.60 0.047 103 1.2428 215 0.0001 4.63*10-14

Peak No

PPy-Sb2O3 (100%)


Value

Crystallize size


1 13.88 0.047 153 6.3749 170 0.0007 2.89*10-14

2 27.80 0.047 1907 3.2065 174 0.0003 3.02*10-14




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3 28.48 0.047 210 3.1314 174 0.0003 3.03*10-14

4 32.20 0.047 713 2.7776 175 0.0003 3.09*10-14

5 35.26 0.047 107 2.5433 177 0.0002 3.14*10-14

6 46.10 0.047 733 1.9673 183 0.0002 3.37*10-14

7 54.30 0.047 47 1.6880 189 0.0001 3.60*10-14

8 57.28 0.094 220 1.6071 96 0.0003 9.26*10-15

9 59.20 0.047 140 1.5595 194 0.0001 3.77*10-14

10 64.38 0.047 53 1.4459 199 0.0001 3.98*10-14

11 68.90 0.047 87 1.3617 203 0.0001 4.19*10-14

12 74.10 0.071 183 1.2784 140 0.0001 1.96*10-14

13 76.32 0.047 123 1.2467 214 0.0001 4.61*10-14

Peak No

Pure Sb2O3


Value

Crystallize size


1 13.80 0.047 253 6.4117 170 0.0007 2.89*10-14

2 27.72 0.118 2957 3.2155 69 0.0009 4.80*10-15

3 28.42 0.071 430 3.1379 115 0.0005 1.33*10-14

4 32.10 0.094 1037 2.7861 87 0.0006 7.72*10-15

5 35.06 0.047 273 2.5573 177 0.0002 3.13*10-14

6 46.02 0.094 1130 1.9760 91 0.0004 8.42*10-15

7 54.56 0.047 980 1.6806 190 0.0001 3.61*10-14

8 58.84 0.047 67 1.5681 193 0.0001 3.76*10-14

9 59.14 0.071 180 1.5609 128 0.0002 1.65*10-14

10 64.10 0.071 90 1.4516 131 0.0002 1.74*10-14

11 67.22 0.047 70 1.3916 202 0.0001 4.11*10-14

12 74.04 0.047 263 1.2793 211 0.0001 4.47*10-14

13 76.24 0.047 103 1.2478 214 0.0001 4.61*10-14

Table.3 Crystallographic parameters of pure PPy, PPy-Sb2O3 nanocomposites and pure Sb2O3 nPs

4.4. Thermogravimetric analysis

The thermogravimetric analysis of pure PPy, PPy-

Sb2O3 (25-100%) nanocomposites and pure Sb2O3 nPs is

shown in Fig.6. To investigate the weight loss of the as-

synthesized pure PPy, PPy-Sb2O3 (25-100%) nanocomposites

and pure Sb2O3 nPs samples, the thermogravimetric analysis

has been carried out in a nitrogen atmosphere. In order to see

the effect of temperature on the thermal behavior of the

polymer thermogravimetric analysis of PPy-Sb2O3

nanocomposites has been carried out from 25-500 ºC

temperature. To investigate the thermal properties and the

interaction between PPy and Sb2O3, TGA analysis has been

carried out through decomposition curve. From the Fig.6 (a)

pure PPy undergoes two-step decompositions are observed.

The first one is appeared at 110 ºC which is due to the removal

of adsorbed water resulting with a weight loss of 53.99%. The

second step of decomposition starts from 200 ºC and goes up

to 450 ºC with about 26.31% weight loss. Finally the residual

mass and residual temperature of pure PPy is 19.70 and

497.8 ºC. Degradation of PPy-Sb2O3 (25%) nanocomposite

takes place in five steps. The first three steps of weight loss

observed at 200 ºC is due to the removal of adsorbed water and

the remaining second step (between 200 ºC and 450 ºC) of

weight loss is due to the breakdown of the polymer backbone

in the nanocomposites as shown in Fig. 7 (b).

Fig.6 TGA spectra of pure PPy (a), PPy-Sb2O3 nanocomposites (b,c,d) and

pure Sb2O3 nPs (e)

Pure PPy

Mass

Change Mass

Residual

Mass

Residual

Temp

Stage: 1 -53.99

19.70 497.80

Stage: 2 -26.31

Stage: 3 -

Stage: 4 -

Stage: 5 -

PPy-Sb2O3 (25%)

Mass

Change Mass

Residual

Mass

Residual

Temp




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Stage: 1 -3.07

70.63 497.70

Stage: 2 -2.02

Stage: 3 -4.03

Stage: 4 -4.31

Stage: 5 -15.94

PPy-Sb2O3 (50%)

Mass

Change Mass

Residual

Mass

Residual

Temp

Stage: 1 -3.21

73.15 498.00

Stage: 2 -1.97

Stage: 3 -4.32

Stage: 4 -3.73

Stage: 5 -13.62

PPy-Sb2O3 (100%)

Mass

Change Mass

Residual

Mass

Residual

Temp

Stage: 1 -1.23

85.06 497.08

Stage: 2 -0.43

Stage: 3 -1.62

Stage: 4 -1.59

Stage: 5 -2.08

Stage: 6 -7.99

Pure Sb2O3

Mass

Change Mass

Residual

Mass

Residual

Temp

Stage: 1 -3.41

88.88 497.90

Stage: 2 -3.51

Stage: 3 -4.20

Stage: 4 -

Stage: 5 -

Stage: 6 -

Table.4 TGA parameters of pure PPy, PPy-Sb2O3

nanocomposites and pure Sb2O3 nPs

The residual mass and residual temperature of PPy-Sb2O3

(25%) nanocomposite is 70.63 and 497.7 ºC respectively.

Mass changes, residual mass, residual temp of pure PPy, PPy-

Sb2O3 (25-100%) nanocomposites and pure Sb2O3 nPs are

shown in Table.4.The mass change of PPy-Sb2O3 (25-100%)

nanocomposites have five stages of weight loss are obtained

for this nanocomposites while the spectrum pure Sb2O3 nPs

have two weight loss appeared in which the weight loss is

decreased with increasing Sb ion concentration and the

residual mass of PPy-Sb2O3 (25-100%) nanocomposites are

70.63 (25%), 73.15 (50%), 85.06 (100%). This data clearly

reveals the residual mass are increased Sb ion content and

with have constant residual temperature [13,14]. By

comparing the thermo graphs of synthesized are pure PPy and

nanocomposites, one can be understood, the different thermal

behavior of the materials. The residual mass increased with

the ionic concentration of Sb2O3 in PPy-Sb2O3 nanocomposite

materials. These results show that the PPy-Sb2O3

nanocomposites materials have remarkable improvement in

thermal stability. These results confirm the strong interaction

between polypyrrole and Sb2O3 forming a stable

nanocomposites.

4.5. Differential scanning calorimetric analysis

Differential scanning calorimetric spectrum of pure

PPy, PPy-Sb2O3 (25-100%) nanocomposites and pure Sb2O3

nPs were shown in Fig.8. Fig. 7 (a) shows the DSC of pure

PPy have broad endothermic peak appeared at around 370.3 ºC, this peak reveals the removel of water molecules from the

pure PPy molecules. DSC spectrum of pure PPy have sharp

exothermic peaks appeared, exothermic peak was shown at

about 95.4 ºC, which was the complex peak, area of this peak

is 756.5 J/g; the onset and endset temperature of the complex

peak is 65.2 ºC, 110.3 ºC respectively, this is presumably due

to the polymer decomposition [15].

Fig.7a

Fig.7b




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Fig.7c

Fig.7d

Fig.7e

Fig.7a-7e DSC spectra of pure PPy, PPy-Sb2O3


The DSC spectrum of PPy-Sb2O3 (25-100%)

nanocomposites is shown in Fig.7 (b-d). The exothermic peaks

appeared in the PPy-Sb2O3 spectrum which named the

complex peaks. From PPy-Sb2O3 (25-100%) nanocomposites

spectrum which have complex peaks and the area of this

complex peaks are 5.481 J/g, 17.150 J/g, and 94.200 J/g. To

compare these nanocomposites, the area of the complex peaks

is increased with increasing the Sb2O3 concentration. The

peaks indicating that, the polymer decomposition was found to

be present in all ratios (25-100%) of nanocomposites. The

peaks indicating that the polymer decomposition was found to

be present in PPy-Sb2O3 (25-100%), but that was clearly

absent in pure Sb2O3 nPs samples. Despite the degradation of

PPy-Sb2O3 (25-100%) nanocomposites samples indicating the

gradual enhancement of thermal stability of the polymer chain

with increasing the amount of Sb2O3. The exothermic peak

disappeared for pure Sb2O3 sample, indicating strong

interaction of the oxide with the polymer chain [16].

4.6. Scanning electron microscopic studies

Scanning electron microscopy (SEM) images of the

pure PPy, PPy-Sb2O3 (25-100%) nanocomposites and pure

Sb2O3 nPs are shown in Fig. 8(a-e). The micrographs of pure

PPy powder (Fig.8a) show big globular clusters of polymers.

The surface morphology of pure PPy changed completely,

when it was converted to the nanocomposites with Sb2O3

(Fig.8b-d), which established the interaction of Sb2O3 surface

with the polymer chain. The white colour is Sb2O3 nPs and

light coloured shell is PPy in the nanocomposites. The

prepared nanocomposite exists as relatively loose aggregates

of PPy-Sb2O3 with crystallize size of 100–250 nm which is

observed from SEM study. The amorphous polypyrrole matrix

can restrict the further growth of Sb2O3 nanocrystals and avoid

their further aggregation in the chemical reaction process.

According to above results, it can be summarized that, the

parameter modulation of PPy in presence of Sb2O3 nPs affects

not only the final morphology but also the structure of Sb2O3

nPs within the PPy-Sb2O3 nanocomposites.

Fig.8a




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Fig.8b

Fig.8c

Fig.8d

Fig.8e

Fig.8a-8e SEM images of pure PPy (a), PPy-Sb2O3

nanocomposites (b,c,d), pure Sb2O3 nPs (e)

Succeeded in controlling PPy-Sb2O3 morphology, the

investigation was turned to explore, the formation mechanism

of the PPy-Sb2O3 morphology through characterizing the

intermediates obtained in different reaction stages. The change

in the surface morphology has been observed with increasing

composition of Sb2O3 (25-100 wt %) in PPy-Sb2O3

nanocomposites. The complex, stringy, interconnected

network is a general feature of the morphology of PPy-Sb2O3

nanocomposites. At higher (100 wt%) of nanocomposites, the

connected path way become more and more dense

morphology are observed due to excess doping as the PPy-

Sb2O3 is approached. At this higher percentage of PPy-Sb2O3

nanocomposites; the morphology appears almost foam like

with PPy-Sb2O3 network surrounded by Sb2O3. Thus Sb2O3

provides large conduction island thereby, reducing the

conduction path through the nanocomposites [17].

4.7. Energy dispersive X-ray analysis

Fig. 9(a-e) shows the EDAX spectrum of the pure

PPy, PPy-Sb2O3 (25-100%) nanocomposites and pure Sb2O3

nPs. The corresponding chemical composition is listed in

Table.5. Fig.9a illustrates the element weight (%) of C, O, and

S of pure PPy sample was 69.32%, 24.24% and 6.44%

respectively. It is seen that C, O, S and Sb elements are

detected in the PPy-Sb2O3 (25-100%) nanocomposites, which

indicates that O and Sb-ions have been doped into the PPy

matrix successfully. The spectrum of pure PPy, PPy-Sb2O3

(25-100%) nanocomposites and pure Sb2O3 nPs shows of the

carbon molecules weight % are 69.32%, 40.66%, 30.02%,

17.87% and 14.80% which is element composition in which

decreasing trend is appeared for the same element composition

changes were obtained for oxygen and sulfur molecules

weights, and the weight % of antimony ion are 35.72 %, 49.98

%, 62.05 % and 85.20 %, for this chemical composition

increasing trend was appeared. As shown in Fig.9b an element

like carbon, sulfur, oxygen and antimony of PPy-Sb2O3

nanocomposite samples which compare due to pure PPy, the

element contents of carbon, oxygen and sulfur was decreased,




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Antimony alone increased with increasing the concentration of

Sb2O3 nanoparticles [18].

Fig.9 EDAX spectra of pure PPy (a), PPy-Sb2O3

nanocomposites (b,c,d) and pure Sb2O3 nPs (e)

Sample

Name

Weight (%)

Carbon Oxygen Sulfur Antimony Total

Pure

PPy 69.32 24.24 6.44 - 100

PPy-

Sb2O3

(25%)

40.66 19.60 4.02 35.72 100

PPy-

Sb2O3

(50%)

30.02 17.35 2.65 49.98 100

PPy-

Sb2O3

(100%)

17.86 18.24 1.85 62.05 100

Pure

Sb2O3 14.80 - - 85.20 100

Table.5 Element analysis data of pure PPy, PPy-Sb2O3


The element contents of PPy-Sb2O3 (25-100%)

nanocomposites show a higher Sb contents due to the

formation of a large amount of Sb2O3.

5. Conclusion

The FTIR analysis is carriedout for pure PPy, Sb2O3

nPs and PPy-Sb2O3 (25-100%) nanocomposites

systematically. The characteristics bands were observed for

the corresponding materials. From the results, one can

conclude that, the wavenumber region is shifted to higher

values after Sb ion absorption. The results indicate that the co-

ordination bond formed between the long pair of electrons of

the atom in the PPy chain with the orbit of Sb atom of Sb2O3,

indicating the strength of PPy-Sb2O3 nanocomposites have

been synthesized successfully and the observed shift which

indicates the interaction between PPy and Sb2O3 nPs. UV-

visible spectra results indicates that the absorption bands

which are correspond to the transition of π-π*. From the tauc

plot, one can conclude that the band gap energy is calculated

for each case of materials. Among the materials, the band gap

energy (3.46 eV) is obtained for pure PPy. The band gap is

decreased with increasing Sb2O3 concentration and this

indicates the PPy-Sb2O3 interactions are significantly

increased by increasing the Sb2O3 concentration loading to

reduce the energy level intervals. X-Ray diffraction studies

suggest the crystallographic nature of the materialsand from

the report, we analyze the XRD patterns of pure PPy, Sb2O3

nPs and PPy-Sb2O3 nanocomposites is in a systematic manner.

The amorphous peak of pure PPy was appeared in addition to

sharp peak, but the other patterns indicates the crystalinity was

greatly improved the with addition of Sb2O3 form the

nanocomposites. From the crystallite size calculations, the

average crystallite size of PPy-Sb2O3 (25 wt%), PPy-Sb2O3

(50 wt%) and PPy-Sb2O3 (100 wt%) are 97 nm, 170 nm and

176 nm respectively. From this, one can inferred that the

lowest average crystallite size is observed for PPy-Sb2O3

(25%). The strain and dislocation density calculation and the

data suggest the crystallographic nature and defects of the

materials. Thermogravimetric results of the pure PPy, Sb2O3

nPs and PPy-Sb2O3 (25-100%) nanocomposites suggest that

thermal behavior and stability of the materials and the number

of stages of decomposition may vary depending upon the

materials. In this report, the lowest number of stages (2) is

observed for pure PPy. The residual mass of PPy-Sb2O3 (25-

100 wt%) is increased, when the composition increase from

PPy-Sb2O3 (25 wt%) to PPy-Sb2O3 (100 wt%). This is

because, the increase of loading amount of Sb2O3 in the matrix

of PPy, but the residual temperature is almost constant for all

the cases. From the differential scanning calorimetric analysis,

one can reveal the stages in which the molecules of various

categories eliminating from the surface. The exothermic and

endothermic peaks suggests that the polymer decomposition is

found in the case of PPy-Sb2O3 nanocomposites. These kinds

of analysis help us to estimate the thermal stability of pure

PPy, Sb2O3 nPs and PPy-Sb2O3 (25-100%) nanocomposites. In

this report, the surface morphological analyses of pure PPy,

Sb2O3 nPs and PPy-Sb2O3 (25-100%) nanocomposites are

carriedout successfully. Actually, the particles are not in

spherical in size for the all the cases. Instead, the particles are

agglomerated initially and the some square shaped particles

are also found and also there are some surface modifications,

due to the agglomeration of the particles, so that the core shell

like structure is formed on the surface of PPy matrix and this

can be seen clearly from the morphological data. From the

EDAX analysis, the elemental composition of pure PPy,

Sb2O3 nPs and PPy-Sb2O3(25-100 wt%) is estimated clearly.

From the increasing trend of antimony, one can inferred the

loading amount of Sb2O3 in the matrix of PPy. This kind of

analysis helps us to gain more information about the structure

and behavior of the materials.




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Synthesis and Characterization of Polypyrrole-Antimony ......nanocomposites . PPy-Sb 2 O 3...

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